DRIVING ON THE INTERSTATE (I-90 MT), ON CRUISE CONTROL, BRAKING FOR A CAR IN FRONT GOING SLOWER, FOUND THAT NO BRAKING OCCURRED, SUDDEN ACCELERATION TO 90 MPH, TRIED TO CHANGE GEARS, TURN OFF ENGINE, PUMP BRAKES WITHOUT RESULTS, THEN GLANCING BLOW TO VEHICLE IN FRONT, NO AIRBAGS DEPLOYED, BAILED OFF ROAD INTO BURROW PIT, EVENTUALLY SLOWED. SEE KARL TYLER WORKORDER #342136.